1. Field of the Invention
The present invention relates generally to the field of preventing injury to the operator of machinery which includes a hose through which a fluid is pumped under high pressure. More specifically and in the preferred embodiment, the invention relates to the protection of operators of high pressure and high velocity sewer cleaning equipment which uses high pressure water jetting for the cleaning of sewer laterals.
2. Description of the Prior Art
Several types of sewer and catch basin cleaning machines are available on the market. Two types of such machines are manufactured by the assignee of the present invention, including the CAMEL.RTM. machines which include sewer and catch basin cleaners and the "CAMEL.RTM. JET" machines which are principally used for sewer cleaning without catch basin vacuuming.
In both types of machines, a hose reel is provided for containing up to 800 feet or more of a hose through which water is pumped at high pressure during the sewer cleaning operation. Pressures as high as 2500 psi or more are utilized with a jetting nozzle having reverse nozzle openings which, in effect drive the nozzle into the sewer lateral pulling hose behind. The nozzles create a cutting and loosening action within the sewer laterals so that debris is loosened and carried by water flow to a catch basin or manhole. In those machines including vacuum systems, a vacuum hose may be located on a hydraulic boom for removing material, including material removed from the laterals into a debris tank loaded on the truck mounted machine. A machine of this nature is disclosed in the Wurster, et al U.S. Pat. No. 4,134,174 entitled "Sewer And Catch Basin Cleaner", issued on Jan. 16, 1979. This patent also discloses and claims modern machines which include water circulation systems to allow purification of the water collected in a debris tank for reuse in a water jetting operation.
The hose reel in the aforementioned type of equipment may be mounted within an open area behind the truck cab or even in front of the truck, depending on the desired end use for the machine. In both cases, the hose reels are hydraulically driven to wind the hose onto the reel after the jetting procedures have unwound the hose. Pulling the hose against the pressure of the jetting nozzle adds to the effectiveness of the lateral cleaning operation. Another type of machine is the "CAMEL.RTM. JET" which does not include the vacuum system but does include the hose reel and high pressure jetting equipment described above. In this particular machine, the hose reel is mounted with its axis perpendicular to the axis of the truck and aligned so that the hose is unwound at the rear of the truck body. It should be understood that the reel may also be positioned in front of the chassis if desired. A lever, known as a level winder, is provided for steering the hose in order to help wind the hose on a reel and further to assist in aligning the hose with the entrance to a catch basin or manhole, and into a sewer lateral.
One of the significant problems associated with the use of this type of equipment is the potential for operator injury in the event that the high pressure hose were to burst or a repair coupling were to come loose during use. Concerning the latter situation, newly supplied hoses are continuous, without interruption throughout their length. However, it is quite common practice to utilize repair couplings in areas where a hose later becomes abraded due to usage under relatively deleterious working conditions, or is cut or otherwise damaged. The hoses are repaired by severing to remove the damaged area and reconnected with the use of repair couplings. Until recently, there were no standards or standardized methods for repairing or testing damaged sewer hose or couplings for sewer hose even now only a voluntary standard exists are published by the National Solid Waste Management Association. Invariably, an operator must stand relatively close reel and catch basin or manhole for normal operation. The operator needs to visually look into the manhole for guiding the hose into the sewer lateral. This is also true where a vacuum hose is used in conjunction with a high pressure hose. A vacuum hose is generally supported from a separate boom, or by other means. Thus, visibility of the catch basin or manhole will become particularly vital during the initial set up and during retrieval of the high pressure hose nozzle and/or vacuum hose. In such cases, it is obvious that an operator will need an access to the manhole and must position himself in the proximity of both hoses. The problem is particularly troublesome if the hose were to burst or a coupling were to fail at the area between the hose reel and the location where the hose enters the manhole. Here, the end of the hose can fly wildly about under the high pressure typically utilized, creating risk of injury by the end of the hose or coupling and by the high powered water spray. Damage to the hose itself occurs through the lifetime of the equipment as the hose encounters potentially sharp obstacles within the sewer lateral, rocks, roots, etc. Obviously, damage to the hose because of such deleterious action require repair couplings to be installed regularly in the field.
The general problem has been recognized since at least 1984 by the assignee of the present invention, and as illustrated in one of its brochures published about that time, a transparent shield was provided around the upper approximately 90.degree. of the hose reel in the general vicinity of where an operator would stand.
Another type of high velocity sewer flushing machines are made by Sreco as described in its product bulletins 3000 and 3045. The latter product bulletin describes the SAFE-WAY.RTM. machine, which includes a cabinet extending from the rear of the truck in the vicinity of the hose reel. The cabinet includes components which are assembled on site and a clear shatter-proof view window so that the hose can be seen from the control panel area. The cabinet is spaced above the roadway so that the hose can be seen below the level of the cabinet, several inches above the manhole rim. The device is relatively cumbersome to use and disassembled and reassembled as the sewer flushing equipment is moved from job site to job site. In addition, it is difficult to manipulate the hose when it is fed through the elongate compartment.
It will be observed from the photograph of these prior art brochures that the prior device must be used on a relatively level area and that there is little or no available entry of a vacuum hose. The lowermost shield also requires relatively cumbersome disassembly when the truck or trailer is moved from one location to another. It is necessary to use mirrors (not shown in product bulletins) to see into the manhole. It is also possible during operation, that the pressure hose may be moved very close to the operator with a portion exposed between the lowermost part of the shield and the street level. This may occur as the hose is unwound and moves across the reel towards the operator during the winding and unwinding operation.
Another device providing shielding means for the upper portion of a high pressure hose is shown in the attached advertisement of Underground, Inc. Here, a catch basin or manhole cleaner is supported by a mobile trailer. It is to be noted that no protection is provided between the lowermost marginal edge of the shielding housing and the catch basin or manhole.
A containment system which would prevent operator injury and permit hose manipulation and which otherwise overcomes the shortcomings of the devices of the prior art would represent a significant advance in this technology.